Security researchers say efforts by Hangzhou Xiongmai Technology are likely to fail due to complexity of threat

BEIJING—Security experts are questioning efforts by a Chinese electronics company to fix problems with webcams hijacked in a major attack on U.S. internet infrastructure, highlighting the complexity of the security threat posed by internet-connected devices.

In a statement released through social media on Monday, surveillance-camera manufacturer Hangzhou Xiongmai Technology Co., said it had issued software patches and planned to recall webcams from the U.S. after reports linked the devices to the massive denial-of-service...